Scaled bilateral teleoperation using discrete-time sliding mode controller

In this paper, the design of a discrete-time slidingmode controller based on Lyapunov theory is presented along with a robust disturbance observer and is applied to a piezostage for high-precision motion. A linear model of a piezostage was used with nominal parameters to compensate the disturbance acting on the system in order to achieve nanometer accuracy. The effectiveness of the controller and disturbance observer is validated in terms of closed-loop position performance for nanometer references. The control structure has been applied to a scaled bilateral structure for the custom-built telemicromanipulation setup. A piezoresistive atomic force microscope cantilever with a built-in Wheatstone bridge is utilized to achieve the nanonewtonlevel interaction forces between the piezoresistive probe tip and the environment. Experimental results are provided for the nanonewton-range force sensing, and good agreement between the experimental data and the theoretical estimates has been demonstrated. Force/position tracking and transparency between the master and the slave has been clearly demonstrated after necessary scalin

Function based control for bilateral systems in tele-micromanipulation

Design of a motion control system should take into account (a) unconstrained motion performed without interaction with environment or any other system, and (b) constrained motion with system in contact with environment or other systems. Control in both cases can be formulated in terms of maintaining desired system configuration what makes essentially the same structure for common tasks: trajectory tracking, interaction force control, compliance control etc. The same design approach can be used to formulate control in bilateral systems aimed to maintain desired functional relations between human and environment through master and slave motion systems. Implementation of the methodology is currently being pursued with a custom built Tele-micromanipulation setup and preliminary results concerning force/position tracking and transparency between master and slave are clearly demonstrated

Development of a micromanipulation system with force sensing

This article provides in-depth knowledge about our undergoing effort to develop an open architecture micromanipulation system with force sensing capabilities. The major requirement to perform any micromanipulation task effectively is to ensure the controlled motion of actuators within nanometer accuracy with low overshoot even under the influence of disturbances. Moreover, to achieve high dexterity in manipulation, control of the interaction forces is required. In micromanipulation, control of interaction forces necessitates force sensing in milli-Newton range with nano-Newton resolution. In this paper, we present a position controller based on a discrete time sliding mode control architecture along with a disturbance observer. Experimental verifications for this controller are demonstrated for 100, 50 and 10 nanometer step inputs applied to PZT stages. Our results indicate that position tracking accuracies up to 10 nanometers, without any overshoot and low steady state error are achievable. Furthermore, the paper includes experimental verification of force sensing within nano-Newton resolution using a piezoresistive cantilever endeffector. Experimental results are compared to the theoretical estimates of the change in attractive forces as a function of decreasing distance and of the pull off force between a silicon tip and a glass surface, respectively. Good agreement among the experimental data and the theoretical estimates has been demonstrated

Model following control with discrete time SMC for time-delayed bilateral control systems

This paper proposes a new algorithm based on model following control to recover the uncompensated slave disturbance on time delayed motion control systems having contact with environment. In the previous works, a modified Communication Disturbance Observer (CDOB) was shown to be successful in ensuring position tracking in free motion under varying time delay. However, experiments show that due to the imperfections in slave plant Disturbance Observer (DOB) when there is rapid change of external force on the slave side, as in the case of environment contact, position tracking is degraded. This paper first analyzes the effect of environment contact for motion control systems with disturbance observers. Following this analysis, a model following controller scheme is proposed to restore the ideal motion on the slave system. A virtual plant is introduced which accepts the current from the master side and determines what the position output would be if there was no environment. Based on the error bet ween actual system and model system, a discrete time sliding mode controller is designed which enforces the real slave system to track the virtual slave output. In other words, convergence of slave position to the master position is achieved even though there is contact with environment. Experimental verification of the proposed control scheme also shows the improvement in slave position tracking under contact forces

Design and control of laser micromachining workstation

The production process of miniature devices and microsystems requires the utilization of non-conventional micromachining techniques. In the past few decades laser micromachining has became micro-manufacturing technique of choice for many industrial and research applications. This paper discusses the design of motion control system for a laser micromachining workstation with particulars about automatic focusing and control of work platform used in the workstation. The automatic focusing is solved in a sliding mode optimization framework and preview controller is used to control the motion platform. Experimental results of both motion control and actual laser micromachining are presented

Açık döngülü piezo-elektrik doğrusal sürücüler için histerez telafisi

Bu bildiride, açık döngülü piezo-elektrik doğrusal sürücüler için yüksek çözünürlükte histerez telafisi gösterilmektedir. Piezo-elektrik malzemelerde yapıları gereği mevcut olan doğrusalsızlıklar, Bouc-Wen modeli kullanılarak model tabanlı bir kontrol algoritması ile telafi edilmiştir. Telafi için kullanılan yöntemin histerez davranışında zaman, değişen frekans ve farklı hareket genişliği nedenleriyle görülen değişimler altında başarılı sonuçlar verdiği gösterilmiştir. Piezo-elektrik sürücülerin yer değiştirme bilgilerini elde edebilmek için yüksek çözünürlüklü lazer interferometre sisteme entegre edilmiş ve lazer interferometreden elde edilen ölçümler döngüyü kapatmak üzere bir geri besleme olarak kullanılmıştır. Histerez döngüsünün telafisi sonucu yer değiştirme gerilimi ve gezinme aralığı arasındaki doğrusallaşma davranışını gösteren muhtelif benzetimler ve deneysel sonuçlar sunulmaktadır

Bilateralno upravljanje zasnovano na zadacima za primjene u mikrosustavima

Design of a motion control system, convenient for a wide range of applications in industry, space, biology, medicine, particularly including more than one physics environment is very important. Well known control architectures like trajectory tracking, compliance control, interaction force control are scientific milestones which has common control task: to maintain d esired system configuration. In this concept, motion control system can be an unconstrained motion-performed interaction with neither environment nor any other system, or constrained motion-system in contact with environment and/or other systems. This paper provides the function based design approach to formulate control of constrained system particularly bilateral systems in micromanipulation applications. The control objective a imed to maintain desired functional relations between human and environment defining convenient tasks and their proper relations on master and slave motion systems. Preliminary results concerning position tracking, force control and transparency between master and slave systems are clearly demonstrated.Sinteza slijednog sustava prikladnog za široki raspon primjena u industriji, svemiru, biologiji, medicini te posebno za primjene koje obuhvaćaju više raličitih fizikalnih okruženja, vrlo je važna. Dobro poznate strukture upravljanja poput slijeđenja trajektorije, usklađenog upravljanja i upravljanja interakcijskom silom predstavljaju znanstvene prekretnice koje imaju zajednički upravljački cilj: održavanje željene konfiguracije sustava. U ovom konceptu, slijedni sustav može biti sustav bez ograničenja i bez interakcije s okolinom ili ostalim sustavima, odnosno može biti sustav s ograničenjima koji je spregnut s okolinom i/ili drugim sustavima. Ovaj članak opisuje funkcijski zasnovanu sintezu sustava upravljanja za sustav s ograničenjima, a posebno za bilateralne sustave u mikromanipulacijskim primjenama. Cilj upravljanja je održavanje željenih funkcionalnih relacija izmežu čovjeka i okoline definirajući prikladne zadaće i njihove odgovarajuće relacije za glavni i podređeni slijedni sustav. Preliminarni rezultati vezani uz upravljanje pozicijom, upravljanje silom te veza izmeđ u glavnog i podređ enog sustava su jasno prezentirani

Galvanometrik sistemin lazerle yüksek hassasiyette işaretleme için yapay sinir ağı tabanlı modellenmesi

Bu çalışmada bir galvanometrik (galvo) lazer ışın demeti yönlendirme sisteminin yapay sinir ağları tabanlı kinematik modeli sistemin yüksek hassasiyette işaretleme, kaynaklama ya da lehimleme işlemlerine yönelik sunulmaktadır. Galvo sistem lazer ışın demeti ile yüksek hızlarda tarama yapabildiğinden hızlı işlemler içeren uygulamalar için güçlü bir araç olma özelliği taşımaktadır. İşaretleme yapılırken kullanılması istenen 2 boyutlu desenlerin bilgisayar destekli tasarım (CAD) ile hazırlanmış çizimler olarak sağlanabilmesi sisteme kullanım kolaylığı ve esneklik kazandırmaktadır. Çizimler önce MATLAB yazılımı kullanılarak grafik olarak çözümlenmiş ve x-y referans veri noktaları şeklinde değerlenmiş, ardından ise C programlama dili kullanılarak hazırlanmış bir kod içerisinde diziler halinde kaydedilmiştir. Bu C dosyasına, sistem yazılımı içerisinde atıfta bulunularak ana rutin tarafından referans veri kaynağı olarak kullanılması sağlanmaktadır. Sistemin teorik kinematik modeli çıkarılarak benzetimleme yapıldığında, ilgilenilen bölgede sistemin neredeyse doğrusal biçimde davrandığı görülmektedir. Sistem pratikteki uygulamalar için yapay sinir ağları yaklaşımı kullanılarak modellenmiştir. Modelin, dönme uzayı ve görüntü alanı üzerindeki ölçülen konumlara göre doğrulaması yapılmıştır. Farklı biçimindeki referans şekilleri takip etmeye yönelik deney sonuçları %4 ve altında hata payları ile yüksek hassasiyetin yakalandığını göstermiştir

Task based bilateral control for microsystems application

Design of a motion control system, convenient for a wide range of applications in industry, space, biology, medicine, particularly including more than one physics environment is very important. Well known control architectures like trajectory tracking, compliance control, interaction force control are scientific milestones which has common control task: to maintain desired system configuration. In this concept, motion control system can be an unconstrained motion-performed interaction with neither environment nor any other system, or constrained motion-system in contact with environment and/or other systems. This paper provides the function based design approach to formulate control of constrained system particularly bilateral systems in micromanipulation applications. The control objective aimed to maintain desired functional relations between human and environment defining convenient tasks and their proper relations on master and slave motion systems. Preliminary results concerning position tracking, force control and transparency between master and slave systems are clearly demonstrated

An efficient and scalable meeting minutes generation and presentation technique

Meetings are essential for a group of individuals to work together. An important output of meetings is minutes. Taking and distributing minutes is a time consuming task. Also, any new member of a meeting series will not be able to easily refer to old minutes if they are in written or e-mail format. Our contribution to this problem is to propose a new approach for taking meeting minutes that will allow dynamic and cooperative note taking. In addition, resulting minutes will allow any new participant to spend a smaller integration time